1. Field of the Invention
The present invention relates to a washing water filtering apparatus for a dish washing machine, and particularly to an improved washing water filtering apparatus for a dish washing machine capable of preventing filters from being clogged by wastes, so that it is not necessary to clean the filters after a dish washing operation is completed, and preventing water pollution by effectively filtering the washing water of the dish washing machine.
2. Description of the Conventional Art
FIG. 1 shows a conventional dish washing machine equipped with a washing water filtering apparatus, which includes a downwardly protruded cylindrical waste gathering box 1a formed at the lower surface of a casing 1 constituting a body of a dish washing machine.
A dish rack 2 is disposed at an upper portion inside the casing 1.
A spray arm 11 having a plurality of spray nozzles 12 a disposed at an inner lower portion of the casing 1 so as to spray washing water upwardly.
A side opening 3a having an introduction tube 6 is formed at the side surface of the waster gathering box 1a.
In addition, a drain opening 3b is formed at the bottom of the waste gathering box 1a, and a drainpipe 8 is connected to the drain opening 3b.
A conical shape fine-meshed filter 4 is provided at the upper portion of the waste gathering box 1a for filtering food particles.
The lower portion of the waste gathering box 1a is connected to the drainpipe 3b disposed below the waste gathering box 1a.
Meanwhile, a coarse filter 5 is disposed at the lower portion of the fine-meshed filter 4 for filtering bigger size of food particles.
In addition, a circulation pump 7 is connected to the introduction tube 6, and the circulation pump 7 and the spray arm 11 is connected by an ejecting tube 10.
A drain pump 9 is disposed at the drainpipe 8 for draining washing water filtered by the fine-meshed filter 4.
The operation of the washing water filtering apparatus for a dish washing machine will now be explained with reference to the accompanying drawings.
Dishes (not shown) to be washed are placed on the rack 2, and washing water and detergent are properly provided in the dish washing machine.
When water supply operation is finished, the circulation pump 7 pumps washing water to the spray arm 11 through the ejecting tube 10, and the washing water introduced into the spray arm is sprayed upwardly inside the casing 1 through the spray nozzles 12, so that dishes on the rack 2 are washed.
Food particles contained in washing water gather on the bottom of the casing 1, and filtered by the coarse filter 5.
In addition, more smaller food particles of waste are filtered by the fine-meshed filter 4, and washing water of which smaller food particles are filtered is introduced into the spray arm by the circulation pump, and sprayed upwardly inside the casing 1.
When the above-mentioned dish washing operation is finished, the circulation pump 7 stops, and the drain pump 9 is operated, and washing water and wastes gathered at the bottom of the fine-meshed filter 4 by the drain pump 9 are introduced to the outside of the waste gathering box 1a through the drain tube 8.
The above-mentioned operation is finished, a dish rinsing operation is performed. That is, rinsing water is supplied inside the casing 1 in the same manner as the washing water supply operation in cooperation of the circulation pump 7.
After the above-mentioned rinsing water supply operation is finished, a dish dry operation is performed.
The full line arrow of FIG. 1B indicates flows of the washing water when the drain pump operates, and the broken line arrow of FIG. 1B indicate flow of the washing water when the drain pump is not operated.
However, the conventional dish washing machine has disadvantages in that since the washing water containing food particles are filtered by the fine-meshed filter 4 and re-supplied to the dish rack in cooperation with the circulation pump 7, when wastes is filtered by the fine-meshed filter 4, food particles gather at only one side of the fine-meshed filter by suction force of the circulation pump 7.
In more detail, when viewing the food particles gathering process from the line C--C of FIG. 1A which is a center line of the fine-meshed filter 4, food particles gather at the inner circumferential surface 4a of the fine-meshed filter 4 at the side of the circulation pump 7 generating suction force, and at the opposed side, the food particles gather at the outer circumferential portion of the fine-meshed filter 4.
Therefore, the food particles gathered at the inner circumferential portion of the fine-meshed filter by the forcing flow of the washing water containing solid particles are filtered by the drain tube. However, food particles gathered at the outer circumferential portion remain because the flow direction of the washing water is the same as the filtering flow of the washing water, the food particles still gather there. When finishing a user should inconveniently remove the food particles.
In addition, when the nets of the filters are clogged by the food particles, the load of the washing pump increases, effective dish washing operation can not be achieved.